Material handling device



l; R. BCKOFEN MATERIAL HANDLING DEVICE Sept. Z3, 1952 5 sheetslshet 1 Filed Aug. 25, 1947 ,frame/z @gara czjffz Sept 23, 1952 E. R BAcKol-EN 2,611,497

MATERIAL HANDLING DEVICE Filed Aug. 25, 1947 3 Sheets-Sheet 2 Sept. 23, 1952 E. R. BACKOFENV MATERIAL HANDLING DEVICE 3 Sheets-Sheet 3 Filed Aug. 23, 1947 Patented Sept. 23, 1952 MATERIAL HANDLING DEVICE E. Ryan ackofen, Battle Creek, Mich., assigner to Clark Equipment Company,

Buchanan,

Mich., a corporation of Michigan Application AugustZS, 1947, Serial No. 770,318

My invention relates to material handling devices and more particularly to devices designed to lift, transport, and lower stacks of boxes or containers, a ,speciiic example being stacks of boxes rcontaining fruit, vegetables, or the like. Prior practice in handling stacked boxes of this type consisted of theuse of a hand clamp truck being applied to a stack, usually nine high, of boxes and this hand truck being manually operated to transport the stack of boxesto and from.

storage warehouses,` or into box cars or the like. Road inequalities often caused tipping of the stack and falling of the upper boxes which resulted in injury to the fruit, injury to personnel, and loss of time. This method of material handling in the food industry has been expensive in that the time involved in moving individual stacks of boxes by manually operated trucks is excessive and requires a large amount of labor.

Improvements in the prior practice of handling stacks of boxes have consisted of employing a clamping device for attachment to a conventional lift truck, whereby the jaws or clamps which engage the opposite ends ofthe bottom boxes of a plurality of stacks o f boxes are actuated by pivotally mounted arms which move the clamps inwardly and downwardly when engaging the load to be lifted, and outwardly and upwardly when disengaging the load. It will be plainly seen from the above that the maximum width limit of the lifted load is greatly restricted by the use of this type of lifting device because of the arcuity of the path of the jaws or clamps vand the necessity of the clamps engaging the stacks of boxes at the lowest possible points on the bottom boxes. y

. As shown in the co-pending application-of E. RyanBackofen and George L. Turner, Serial No. 649,904, led February 25, 1946, and now Patent No. 2,536,151, granted January 2, 1951, it is intended to improve upon the prior art of handling boxes, containers, or the like by providing a clamping device for attachment to a conventional lift truck, which clamping device is hydraulically operated and consists of clamping ymeans to engage the opposite ends of the bottom boxes of aA plurality of stacks of boxes in order to lift, trans-v port, and lower the stacks of boxes. However,V

greatly limits the size of the load capable of be-V ing lifted. Too, the ice tongs principle of lift- 8 Claims. (Cl. 214-113) ingis used in this device, whereby the gripping force of the jaws or clamps is in proportion to the weight of the load lifted. 4In practice, it has been found in,v this `device that the tines or prongs, which extend inwardly fromthe clamp arms to becomeembedded in the bottom box of the stack to obtain a positive grip on the load, slide upwardly on the side surfaces of the box until the two y opposingV clampshave moved into suii'icientproximity to each otherto laccept and h old the weight of the load.r This-type of-gripping is extremely unsatisfactory becausethe boxes are splinteredat their opposite endsmaking it diiicult to aiiix box labels and dangerous'to later handle the boxes by hand, and the gripping pressure oftentimes is finally exerted against the upper portions of the boxes where they are less sturdy than at the lower portions. l Y

It is therefore anpobject of this invention to provide a material handling device for use in lifting and transporting stacks of boxes or the like whereby a greater distance span between the jaws or clampingmeans is possible, thereby increasing the varietyof sizes of loads capable of being lifted.

It is afurther object of this invention rto provide such a device whereby the actuating means for the clamping action is independently applied so that the clamping pressure is not dependent upon the weight of the lifted load, and can be applied to the load so as to give constant and even pressure and anlimmediate: and positive grip.

Still further/objects of the invention are to utilize the lift mechanisms of a conventional indus-` trial truck of the fork lift type to provide the pressure for actuating the clamping means of the present invention, to provide means on the lifting frame, situated above the clamping means, to4

supplement said clamping means in gripping the stacks of boxes by exerting pressure either on top of the stacks orvonthe outer surfaces of the opposite ends of Atheupper boxes of the' stacksto preventtipping ofthe load, and to provide supports at the upper end ofthevupright mechanism of the industrial truck over which are trained theV conduits or flexible pipe lines,V connecting the hydraulic cylinder of the clamping device tothe hydraulicsystem of the industrial truck, thereby eliminating slacky in these conduitswhich other- .1

wiserwould interferewith operation of the device,A

Other objects of the invention'willvbmmore apparent from the descriptionvofr `the construe-1v tion, operation, and arrangement. of parts here-r inafter related, together with itheaccompanying, drawingsto which referencemay be had for an 3 embodiment of the present invention, wherein:

Figure 1 is a perspective View of my material handling device shown in combination with a conventional industrial truck.

Figure 2 is a view in side elevation of the material handling device shown in assembly with the upright mechanism normally mounted on the front portion of a conventional industrial lift truck.

Figure 3 is a front elevational view of the mechanism shown in Figure 2, with the clamps shown in their closed position.

Figure 4 is a front elevational view of the steadying device employed to engage the top surlaces of the stacks of boxes, showing the cross bracing structure therefor.

Figure 5 is a perspective View of a modified version of my invention with the clamps shown in their open position.

Referring now to the drawings, a conventional industrial truck of the fork lift type is indicated at I. The industrial truck is provided with a conventional lift mechanism, indicated generally at 2, and a conventional tilt mechanism (not shown). The lifi'l mechanism comprises a pair of upright channel members 3, connected at their upper ends by a cross member 4, and a hydraulic cylinder 5', provided with a piston rod 6, which has ahead or yoke 1, secured at its upper end for movement relative to the cylinder 5, when hydraulic pressure is exerted therethrough. At the opposite ends of the piston rod head or yoke 1, are placed rotatably mounted sprockets 8, over which are trained lift chains 9, the upper ends of which are attached to cross bar member I9, secured to the rear face of the uprights, and the lower ends of which are attached to the bodyf portion I I of the lifting device for raising or lowering the lifting' device frame through the hydraulic means of the industrial truck.

Thel lifting device consists of a rigid frame comprising a pair of upright channel frame members, cross bracingv members and a backing plate towhich are secured the various component parts of the clamping device, which device constitutes an important object of this' invention. This entire frame is mounted for guidedvertical movement by roller means disposed in the inner channel portions of the upright mast assembly of the lift truck for vertical movement in raising and lowering the stacks of boxes or the like.

The lifting device frame, indicated generally at I8, comprises a pair of parallel upright channel members I2-, rigidlyjoined in spaced relation at their upper ends by cross member I3, and intermediate their upper and lower ends b'y lcross member I4. At their lower endsr the upright channel members- I2f, `are joined in spaced relation by means ofa backing plate I I, which isv secured to the rear surfaces of thev upright members I2. The rear surface of the backing plate II supports suitably mounted pairs of rollers I5, guided in the channel portions of the upright assembly 3- of the lift truck when thelifting device frame I-8 is lifted or lowered.

The clamping means for engaging the outer surfaces of-the opposite ends of the'bottom boxes ofV a.' stack or plurality of stacks of boxes' comprises a hydraulic cylinder IB- disposed in front ofthe backing platev I Il and which is independent- 1y operatively connected tovthe hydraulic system of the industrial truck. Arranged for cooperation with the hydraulic cylinder-I6 and its related piston rodv I1' are armsv I9 and 20 pivotally mountedon lugs. 3-I and 32 on the backing plate.

which arms are pivotally connected at their lower ends through connections 2I and 22 to lugs or bosses 23 and 24, which are, in turn. rigidly secured to clamp members 25 and 26. Through suitable hydraulic control valve means, the piston I1 may be actuated to move the clamp members toward or away from each other.

The clamp members 25 and 26 are mounted for lateral sliding movement in the same Plane on backing plate I I by means of telescoping rod and sleeve means 21, 28, 29, and 30, which slide one within the other when the clamp members 25 and 26 are opened or closed. These telescoping members are reversely mounted, relative to the two clamp arms, on the lifting device to eliminate the tendency to bind when the clamp members 25 and 26 are actuated. That is, sleeve member 21 is mounted on the upper portion of clamp member 26 and sleeve member 29 is mounted on the lower portion of clamp member 25, while rod member 28` is mounted on the upper portion of clamp member 25 and rod member 30 is mounted on the lower portion of clamp member 26. Free lateral movement for the clamp members 25'and 26 is obtained by supporting the telescoping means combinations in apertured guidesv 33 and 34, carried on backing plate I I.

' In order that the bottom boxes of the stacks of boxes to be lifted are properly clamped at their opposite ends, clamps members 25 and 26 are provided with horizontally extending arms 35 and 36 which are pivotally suspended therefrom by means of a bolt 31, located centrally of the arms 35 and 36. The arms 35 and 36 are pivotally mounted on the clamp members to provide means for centeringthe load and to compensate for minor irregularities in the size of the boxes. The arms 35- andl 36 are each provided with a series of inwardly extending pins or pointed projections 38 loca-ted longitudinally therealong for penetrating the outer surfaces of the opposite ends of the bottom boxes to secure a positive grip on the-load and to prevent slippage.

Inorder to limit the horizontal swinging movement of the arms 35 and 36 about their pivots, there is provided on the undersurfaces of the clamp members 25 and 26, downwardly projecting pins 39 which are tted into transverse slots 46 in thearms 35 and 36, thus limiting the horizontal movement of the arms 35 and 36 so that they will be in alinement when moving into position to enor disengaginga load.` Thus, when the lifting de vice israised, the pulleys are-raised simultaneously therewith, and the hose lines trained thereover. remain'taut allowing no slack lines *to-interfere with the operation of the machine.

To steady the top boxes of the stacks of boxes, there is provided al load compressor device whichv comprises a pair of parallel vertical members, cross bracing therefor anda forwardly extending shelf secured to the upper portions 'of the legs' for resting on the ,tops ofV the stacks of boxes to eliminate tipping. The parallel vertical members 44- and 45Y are securely braced by reinforcing members 46, 41, 48, and 49, and in operation aree movabgy secured in the channel portions of theY upright members I2 of the lifting device for free vertical operation. VAti thel upperends of thever, ticalmembers Maand 45,"the're are securedpfor-f. wardly-extending` brackets 5I) tand ,5 I The for: wardendszofjthese brackets 5I)l and 5I, pivotally supporta'stabilizing member 52 for slight forward and rearwardrocking. movement; The ,member '521.preferably comprises .a sheet metal yportion on whose under surface is secured a `pliable cushion-f;v ing. material such as asponge rubber :pad or the like, for .cushioned stabilizing lcontact-with .the upper Asurfaces ofthe stacks of boxes. lA series of. holes 53 is formed through' the verticalmem'- bers 44. and 45 and longitudinally thereof foriinsertion of pins 54, which limit the'downward movement of :the load compressor. By providing a plurality of holes spaced longitudinally of the vertical members, the loadl compressor may be adjusted so that stacks of boxes vof different heights may be lifted and transported'. The pins 54 are inserted through the holes 5 3 and extend outwardly of the vertical members 44 and 45 so that downward movement of the load compressor is arrested when the outwardly extending portions f the-pins 54 contact the top surfaces o'fthe'upright channel members I 2 of the lifting device frame.. u; u 4.

In opera`tion,the truck I approaches the stacks of boxes'to be lifted with thelifting device in partiallyraised position `"andthe clamp members and 26 in-open-position. When the position of the truck is suchthat the vstacks' of boxes are centered between the clamp membersv 25 and 26 and the stabilizing member 52 is directly over the top of the stacks of boxes, the lifting `device frame is lowered until theweight of the stabilizing member 52 rests upon 'the'tops of the boxes and the pivotally suspended arms and 36 are level with the lower portions of the bottom boxes of the stacks of boxes. Hydraulic pressure is then applied by the truck operator through hydraulic cylinder I6 to close clamp members 25 and 26 until the boxes are rmly grasped between these members. The stacks of boxes are then raised and may be tilted rearwardly to eliminate tipping by actuating the tilt cylinder of the truck. The load is transported to the desired location and lowered to the floor or ground. The clamp members 25 and 26 are opened outwardly to release their grip on the boxes and the lifting device is raised to disengage the stabilizing unit from the top of the stacks of boxes and the truck is free for another operation.

As a modified version of my invention (shown in Fig. 5) I provide, in lieu of the load compressor device for steadying the tops of the stacks to prevent tipping, a pair of vertically extending upright members 55, whose bottom portions are secured to the upper surfaces of the outer portions of sleeve member 21 and rod member 28. suitably secured to the upper ends of upright members are forwardly extending horizontal arms 56, each of which arms is provided on its inner surface with a plurality of inwardly extending pin members 51 which engage the outer surfaces of the opposite ends of the upper boxes of the stacks when clamp members 25 and 26 are closed to engage the load, thus steadying the load and eliminating any tendency to tip.

While various changes may be made in certain details of the illustrated embodiment of the invention herein described, it is intended that the spirit and scope of my invention shall govern and that I shall not be limited to the matters contained in the accompanying drawings.

' tendible.. means horizontally oatingly f mQllnled.

6. I claim;

il. vIn :a lifting lift: means, a'frame, a'pair of forwardlyextending;'laterally spacedhorizontal clamping arms mounted; thereon; hydraulically actuated nexin transverse; alinementbetween said clamping arms, connecting means operatively connecting said hydraulic means. to thehydraulic system of;

said truck, a pair of-pivoted levers mountedgon said lframe,-;the;.upper ends ofsuch levers being pivotallyl connected to opposite ends; of; said exe. tensible means and means pivotally connecting.

zgrrne deviefbf elena 1? .inducing teieseopingl mountingfmeansbetweensaid clamping arms providing'laterally opposed motion of s aid clamping thereon, hydraulically actuated extensiblenieans horizontally, oatingly mounted in transverse alignment between said clamp arms, a pair o f pivoted levers mountedon said frame, the, upper, ends. of said leversgbeing ,pivotally-connected tothe opposite endsl of said extensible means, means pivotally connecting the lower ends of the levers to said clamp arms, and load stabilizing means vertically movable in said frame above said clamp'arms .for steadying the upper portion ofla'loadengaged bythe clamp arms.

" ,4.1 For Vuse with an industrial v truck draulic lift means, a lifting device comprising, a frame, a pair of forwardly extending horizontally spaced load engaging clamp arms mounted thereon, hydraulically actuated extensible means horizontally floatingly mounted in transverse alignment between said clamp arms, connecting means operatively connecting said hydraulic means to the hydraulic system of the truck, a pair of pivoted levers mounted on said frame, the upper ends of such levers being pivotally connected to opposite ends of said extensible means, means pivotally connecting the lower ends of said levers to said clamp arms, and load stabilizing means vertically movable in said frame above said clamp arms for steadying the upper portion of a load engaged by the clamp arms.

5. For use-with an industrial truck having hydraulic lift means, a lifting device comprising, a frame, a pair of forwardly extending horizontally spaced clamp arms mounted thereon, telescoping mounting means between said clamp arms providing laterally opposed motion of said clamp arms, hydraulically actuated extensible means horizontally floatingly mounted in transverse alignment to said clamp arms, a pair of pivoted levers mounted on said frame, the upper ends of such levers being pivotally connected to opposite ends of said extensible means, means pivotally connecting the lower ends of said levers to said clamp arms, and load stabilizing means vertically movable in said frame above said clamp arms for steadying the upper portion of a load engaged by the clamp arms.

6. For use with an industrial truck having hydraulic lift means, a lifting device compris ing. a frame, a pair of forwardly extending horizontally spaced load engaging clamp arms mounted thereon, telescoping mounting means between said clamp arms providing laterally opdevifio aaalimetfltaii. industrial truckv orglike' vehicle havingv hydraulic.

7 posed motion of said clamp arms, hydraulically actuated extensible meanslhorizontally fioatingly mounted in transverselalif'gnment to said? clamp arms,l connecting. means operativelyVv connecting. said hydraulicv means-to the: hydraulic' system otthe truck?, a pairof iai-voted levers mounted oni said trame?, theY upper' ends? of' suchlevers being piy'itally connected. to opposite' ends of said extensbl m'ea'iSf me'as' ll'v'otlly chlietingf the Tower ends ofv said levers to said: clamp' arms', and load stabilizing' xne'ans` vertically movable in said frame above said clam-p arms for4 stead-ying. the* uppenportion of a; load-.engagedby the clamp arms f For usey with an industrial truck having a hydraulic system and a load `supporting carriager a: load engaging: device; comprising; a pair :of forwardly extending: horizontally spaced. diamo armslmounted on the carriage formovement'to'f ward and away from each other, a pair of levers pivotally' mounted intermediate their' ends on thev carriage aboutl axes ei'itendiigllongitudinally of the truck",- horizontaii hydraulitaiiy:Y animated? @"xt'ervi'dble' mearis'l extending? transversely' of the: carriage and: piyotaii-yf mounted.` at the ends thereof to one of tlieends o'f' eaot'- of s'aidllevers', means for ope'ifatively connecting' said hy'cir'aulfA cally actuated. extendible? mean'sto the' hydrauii'o syst'emlof'theftruekg-admeans for pivotal-1y cone' necting the-'other' ofthe ends o'feachl of said1le=' Ve'rS t'o Sid Clrii'p aifis- 8; For use with an; industriali truck. having; a: hydraulic system andi a load supporting; can riage aload er'i'gaging'f devi'c'e comprising;- a;A pairl of vertically spaced-y telescoping mounting. means extending' transversely? of the carriage and carried. thereby, a pair' offorwardly extending horizontally spaced. clamp arms secured to the' ends of said telescopingk means, a pair ofl'evers pivotally mounted intermediate their ends on the carriage about axes extending longitudinally of the truek, horizontal hydraulic actuated exV tendibl'e' means extending transversely of vthe carriage and pivotally mounted at the ends thereof to one of the ends of each of said levers. meansi foropera-tively connecting said hydraulically actuated extendible means to' the' hydraulic systemot the' truck, a-nd means for pivotally oon-V` necting the other of the ends of each of said le' vers to' said clamp arms. .v

E. RYAN BACKOFEN.

REFERENCES CITEDv 'rnegroiioiving references are of record mf the ilfel Ot tliis Apatent:`

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